CRYSTAL GROWING METHOD AND APPARATUS FOR PERFORMING THE SAME Russian patent published in 2008 - IPC C30B15/22 C30B15/14 C30B15/12 

FIELD: processes and equipment for growing large-size crystals with use of double crucible at adding initial material to melt.

SUBSTANCE: method comprises steps of heating growing unit at controlling temperature; adding palletized charge to crucible By means of metering device; approaching seed to surface of melt; drawing upwards rotating seed crystal and automatically controlling diameter of grown crystal due to regulating rate of making up melt level and power supplied to bottom heater. Melt level is sustained during the whole process as H ≤ [1708 x kν/gαΔТ]^1/3 - h where g = 9.8 m/s² -gravity acceleration; α -temperature coefficient of volumetric expansion; h - meniscus height of melt; ΔT- temperature difference of crucible bottom and crystallization front; k - thermal conductivity of melt k = λ/ρС where λ - heat conductivity, ρ - melt density; С - heat capacity of melt at constant pressure; ν - kinematic viscosity of melt. Apparatus for performing the method is also offered. Due to selection of melt level in the result of absence of free convection of melt and due to possibility for controlling crystallization front, it is possible to achieve axial and radial uniformity of crystal and to increase controllability and reproducibility of process. Due to selecting height of walls of outer and inner portions of crucible where R - crystal radius; μ - coefficient of heat removal from crystal surface; λ - coefficient of crystal heat conductance; and melt level on base of control of axial temperature gradient of crystallization front it is possible to improve axial uniformity of crystal.

EFFECT: enhanced quality of crystal, improved efficiency of crucible, less consumption of crucible material.

5 cl, 5 dwg